In U.S. patent application Ser. No. 047,960 (see corresponding PCT International Publication No. WO88/08856, Nov. 17, 1988), it is disclosed that comonomers for propylene may be made by protecting the oxygen of a copolymerizable hydroxy-containing compound by substituting the hydrogen thereof with a silyl group having a minimum steric bulk, i.e., at least about three carbon atoms surrounding it, so that they may be copolymerized in a Ziegler-Natta system. Silylated monomers of the general formula ##STR3## where X can be a variety of connecting moeities, are suggested in the publication.
The peculiar advantage, however, of eugenol as a potential comonomer in its silylated form apparently has not been seen in the prior art, in spite of the fact that a different silylated monomer has been formed from trimethylsilylated engenol. See Horiguchi et al "High Molecular Weight Polysilanes with Phenol Moeities" Macromolecules, 1988, pp. 304-309.